Fossil hunters are used to finding the remains of ancient sea creatures on land miles from shore; primeval oceans had a habit of turning into continents. But when researchers combing northern Pakistan’s Kala Chitta hills found the remains of a 10-foot whale, there was a better and even more intriguing explanation: the ancient whale sported as fine a set of legs as any self-respecting land animal. Ambulocetus natans was about the size of a big male sea lion and tipped the scales at 600 to 700 pounds. Discovered in 52 million-year-old deposits, the fossils contain enough of the creature’s legs, vertebrae and tail to show conclusively what had been only suspected: that ancestors of today’s whales could walk on land much as today’s seals do. The find, reported in the current issue of the journal Science, proves a decade-old theory that a walking whale must have been the missing evolutionary link between ancient four-footed land animals and today’s aquatic mammals.
Ambulocetus had respectable back legs with big feet. But its stubby front feet protruded almost directly from its shoulders, so it must have bumped along the ground on its stomach and chest, according to J.G.M. Thewissen of North-eastern Ohio Universities and colleagues who discovered it. This clumsy gait doubtless prevented the whale from catching much food on land, and so it slipped into the water to dine. To swim, it both undulated its spine and propelled itself with its feet. Why would it want to spend much time on land? To give birth, for one thing. It’s much easier for newborn mammals to emerge into air than into water, and also easier for their mothers to nurse them on land (seals and sea lions still take to the land for mating, for giving birth and for suckling). But the lure of dinner in the deep became too strong, and 50 million years ago whales returned to the sea for good.
Newsweek January 24th 1994
Read the text to find out:
What hypothesis the researchers had?
Que los antepasados de las ballenas de hoy puede caminar sobre la tierra hasta el día de hoy los precintos.
What evidence do they use to support this hypothesis?
Que cuando los investigadores del norte de Pakistán del Kala Chitta colinas encontraron los restos de un pie de 10 ballenas, se produjo un mejor y más intrigante explicación: la antigua ballena sported multa como un conjunto de piernas como cualquier auto-respeto de animales terrestres.
Fossils: Thar she crawls
Fossil hunters are used to finding the remains of ancient sea creatures on land miles from shore; primeval oceans had a habit of turning into continents. But when researchers combing northern Pakistan’s Kala Chitta hills found the remains of a 10-foot whale, there was a better and even more intriguing explanation: the ancient whale sported as fine a set of legs as any self-respecting land animal. Ambulocetus natans was about the size of a big male sea lion and tipped the scales at 600 to 700 pounds. Discovered in 52 million-year-old deposits, the fossils contain enough of the creature’s legs, vertebrae and tail to show conclusively what had been only suspected: that ancestors of today’s whales could walk on land much as today’s seals do. The find, reported in the current issue of the journal Science, proves a decade-old theory that a walking whale must have been the missing evolutionary link between ancient four-footed land animals and today’s aquatic mammals.
Ambulocetus had respectable back legs with big feet. But its stubby front feet protruded almost directly from its shoulders, so it must have bumped along the ground on its stomach and chest, according to J.G.M. Thewissen of North-eastern Ohio Universities and colleagues who discovered it. This clumsy gait doubtless prevented the whale from catching much food on land, and so it slipped into the water to dine. To swim, it both undulated its spine and propelled itself with its feet. Why would it want to spend much time on land? To give birth, for one thing. It’s much easier for newborn mammals to emerge into air than into water, and also easier for their mothers to nurse them on land (seals and sea lions still take to the land for mating, for giving birth and for suckling). But the lure of dinner in the deep became too strong, and 50 million years ago whales returned to the sea for good.
Newsweek January 24th 1994
Read the text to find out:
What hypothesis the researchers had?
Que los antepasados de las ballenas de hoy puede caminar sobre la tierra hasta el día de hoy los precintos.
What evidence do they use to support this hypothesis?
Que cuando los investigadores del norte de Pakistán del Kala Chitta colinas encontraron los restos de un pie de 10 ballenas, se produjo un mejor y más intrigante explicación: la antigua ballena sported multa como un conjunto de piernas como cualquier auto-respeto de animales terrestres.